The Tucker Trimmer tool was designed to help quilter’s quickly and easily trim down units that are made with triangles: half square triangle squares, quarter square triangle squares (hourglass units), and combinations of half square and quarter square triangle squares (combination units) in half inch increments from 1" - 6" finished blocks. It has multiple diagonals which allow you to align ruler guide lines with unit seam lines to quickly locate the exact center of pieced units. This makes trim down easy,precise, and perfect every time. The Tucker Trimmer II trims 3/4" - 5 3/4" finished blocks. The Tucker Trimmer III trims 1" - 12 1/2" finished blocks.